Volumetric systems are mainly used for bearing and slideway lubrication on machine tools, this is a positive displacement system delivering specific amounts of lubricant to the required points. Two types of metering valves are available: the Direct type which operate on full line pressure and the Indirect type which are incorporated into special manifolds and are operated by spring pressure as the main line pressure decays. The former gives a rapid full pressure response, whilst the latter gives a slower output.

This is a positive displacement delivery system: Distributors deliver specific amounts of lubricant to the bearings.

The surplus pump output is returned to the reservoir. This enables the number of points to be varied without major changes to the entire circuit.

Direct and Indirect distributors are available: the former operate as the main line pressure increases and they can be fitted either into a manifold or directly into bearing housings: the latter operate as the main line pressure reduces, delivery to the bearing is by spring.